Confused about Square-D 90A Breaker

[b-boy]

I just added a panel to my detached pole barn. It's a 100A Square D QO panel. I sized all my cable for 90A. I have an existing 60A breaker in my house. My pole barn is running on that. I'd like to upgrade to a 90A breaker.

The panel in my house is a Square D QO. It's at least 15 years old, if not older. The prior owner upgraded to a 200A service sometime during the late 90s or early 2000s. The old 60A breaker was powering an old barn on my property. I had it torn down recently.

I purchased a 90A Square D QO Model # QO290CP. I found it at Loews. It appears to have been a special order that was returned. It was the only one they had in stock. It's slightly longer than the existing 60A breaker, and does not fit into my panel. The connectors appear the same, but if you stand both breakers on their side, the distance between the connectors is slightly greater on the 90A breaker. It's no more than a millimeter in difference, but it just won't click into place.

I assumed a QO breaker would fit any QO panel. How can I locate the correct breaker for my house panel? Is there a number on the box somewhere that I should look for?

 

[ishiboo]

Those connectors float - the breaker should fit. It's possible it is defective which is why it was returned.

All QO breakers have those same dimensions and should be compatible, ignoring the fact that the "plug on neutral" breakers require a plug on neutral panel, and CTL vs non-CTL, 3-phase boards, etc.

 

[rlitman]

There are different QO systems, but that breaker should fit your panel. CP just means "commercial packaging".

https://www.schneider-electric.us/en/faqs/FA241391/

Maybe one of the clips on your breaker was bent? Could it have been dropped? If the "float" in the clip isn't enough to get the breaker to snap in, DO NOT try to bend it.

 

[b-boy]

It's really close, but will just not click into place. That's why I mentioned that the item was returned. You'd think that Lowes would toss it if someone returned it as defective, but I guess I'm making assumptions.

 

[wyliesdiesels]

Can you post some pics?

 

[TRWham]

It's really close, but will just not click into place. That's why I mentioned that the item was returned. You'd think that Lowes would toss it if someone returned it as defective, but I guess I'm making assumptions.

You cannot ever be sure. I have purchased 3 packs of GFCIs off the shelf that someone returned with used devices in the box. HD just put them back on the shelf without close inspection, and that's at a store I generally find to be high quality (apparently it is the home store of THD's CEO).

 

[alfredeneuman]

QO breakers take a bit more "push" than the others for the stabs to fully engage.
The bus stabs have been the same since the beginning.
(EDIT) The way to do it is to clip the non current carrying parts (below the breaker lugs) to the rail, and next the current carrying bus stabs.
If you try to do it all at once you'll fail every time.

 

[b-boy]

I guess I'll try one more time. I usually click the current carrying end first, then the non-current end last. when I remove them, i reverse that.

 

[ishiboo]

I guess I'll try one more time. I usually click the current carrying end first, then the non-current end last. when I remove them, i reverse that.

I'm pretty sure the proper process for QO breakers (at least non-PON) is to clip them in at an angle to the plastic rail, and then rotate it so the bus stabs connect.

 

[alfredeneuman]

If as he said, "the panel is at least 15 years old" the rail may not be plastic, but steel.

 

[sberry]

I am curious. Why are you replacing it? Have you tripped the 60?

 

[b-boy]

I sized my run for 90A, so I'm replacing the 60A. The 60A is an old breaker. It used to trip all the time when it was powering my old barn. That may have been the breaker, or some issues with the old wire run. I'm not sure. I'd rather replace it than have to deal with it on a new circuit.

The 90A was around $50, so it wasn't extremely expensive.

 

[signcrafter]

Curious why you sized it for 90 and not 100 like the sub panel is? A 100 amp breaker is common at most stores.

 

[sberry]

When its used as a service entrance 2 alum is rated at 100. For branch its 90

 

[sberry]

If it tripped a 60 I would want to know why. What loads do you have? It takes quite a bit to trip one up.
Does your new application have the potential to overload it?

 

[Aceman]

You need to clip it onto the plastic outside rail first. That locates the breaker horizontally left-right. Then drop it down onto the bus stabs.

 

[wyliesdiesels]

Curious why you sized it for 90 and not 100 like the sub panel is? A 100 amp breaker is common at most stores.

Because he used #2 al which is max 90a as a branch feeder.

 

[b-boy]

I ran a new circuit and used THHN/THWN 2-2-2-4 copper. It was a ~250ft run inside a 2" conduit.

The tripping was probably due to the old barn's wiring. There was really not much running on it. It was very old. I think there was probably some moisture that was causing my problems. I didn't want to take a chance that the breaker was part of the problem, so I just replaced it.

 

[ishiboo]

I ran a new circuit and used THHN/THWN 2-2-2-4 copper. It was a ~250ft run inside a 2" conduit.

The tripping was probably due to the old barn's wiring. There was really not much running on it. It was very old. I think there was probably some moisture that was causing my problems. I didn't want to take a chance that the breaker was part of the problem, so I just replaced it.

We all assumes you used aluminum. A 90A breaker is fine but you could have used a 100A and theyre easier to find.

 

[b-boy]

I still can't get this thing to click into place. It just won't fully click in. I'm literally leaning on it, but nada. I'm afraid I'll break the panel. I think there is something wrong with the breaker. I'm going to return it.

I appreciate the feedback. I thought I had the wrong breaker type. I'm pretty sure that it's defective.

 

[Norcal]

We all assumes you used aluminum. A 90A breaker is fine but you could have used a 100A and theyre easier to find.

A 90A breaker is the maximum allowed for 2 AWG AL, your giving bad advice.

 

[rlitman]

A 90A breaker is the maximum allowed for 2 AWG AL, your giving bad advice.

Go back to the relevant info in the OP's post:
"THHN/THWN 2-2-2-4 copper. It was a ~250ft run"

 

[rlitman]

I still can't get this thing to click into place. It just won't fully click in. I'm literally leaning on it, but nada. I'm afraid I'll break the panel. I think there is something wrong with the breaker. I'm going to return it.

I appreciate the feedback. I thought I had the wrong breaker type. I'm pretty sure that it's defective.

Sounds that way. My guess is it took a fall from a high shelf right onto the clip.
The thing is, the piece that clips onto the bus is a carefully engineered spring, and if it is deformed, you definitely do not want to put the breaker into service, so if it isn't clicking in, returning it may be your best bet. However, as pointed out above, the current carrying side should be the part you click in last.

 

[sberry]

Or we are trying to put a HOM in QO or the other way around. Now that we know its copper,,,

 

[b-boy]

Or we are trying to put a HOM in QO or the other way around. Now that we know its copper,,,

Everything is definitely QO. I've added 15A/20A breakers to this panel in the past. They were QO, and they always fit. The 60A I tried to swap out is clearly labeled QO. I had no problems removing and replacing that breaker. It seems to have a lot more play in it.

 

[ishiboo]

A 90A breaker is the maximum allowed for 2 AWG AL, your giving bad advice.

You're having some reading troubles. We had assumed the OP used #2 aluminum. He actually used #2 copper. So a 100A breaker is fine.

 

[ctgoodman]

You cannot ever be sure. I have purchased 3 packs of GFCIs off the shelf that someone returned with used devices in the box. HD just put them back on the shelf without close inspection, and that's at a store I generally find to be high quality (apparently it is the home store of THD's CEO).

I bought a 200 amp panel from Lowe’s (online order). When I got home it had a 100 amp panel in it and a cover for a different brand panel altogether. This was sold as a new item. Here Lowe’s commonly does not look at the returns and will shelve them as new. I always check anything now if I have a slight suspicion that it may have been opened before.


Sent from my iPhone using The Garage Journal mobile app

 

[Norcal]

You're having some reading troubles. We had assumed the OP used #2 aluminum. He actually used #2 copper. So a 100A breaker is fine.

I failed reading comprehension 101 This is what I get for assuming too. My apologies I was wrong & it was not the first time nor the last time.

 

[rlitman]

I failed reading comprehension 101 This is what I get for assuming too. My apologies I was wrong & it was not the first time nor the last time.

It's all good. I know you've called me out plenty of times for the same sort of reasons.

 

[b-boy]

You're good. I never mentioned the size or type of wire. The original question was about the breaker and the panel.

 

[signcrafter]

So just go buy a 100 amp breaker that is sold in every store and call it good now that we know it's copper and good to go.

 

[Mr_fixit]

still no picture?

 

[mm08822]

90A is the max size not 100A. Permitted ampacity is reduced to limit voltage drop to approx 3%. The run is 250' long.

 

[Aceman]

90A is the max size not 100A. Permitted ampacity is reduced to limit voltage drop to approx 3%. The run is 250' long.

Where can I find that in the code book?

 

[alfredeneuman]

Where can I find that in the code book?

AFAIK The only place Voltage Drop comes into the Code is that the grounding conductor will be upsized proportionately to the phase conductors where the phase conductors sizes are increased because of voltage drop.

The rest are "informational notes" only, and as such cannot be enforced.

 

[mm08822]

Where can I find that in the code book?

The code doesn't enforce voltage drop but only provides "Informational Notes" on the subject so you won't find it. The allowable ampacities listed in 310.15B are subject to correction factors. VD hasn't made it to the enforced list.

Upsizing a conductor size for vd correction does not mean use the allowable ampacity from 310.15B for this larger size conductor.

Under the concept of minimizing voltage drop, up-sizing the conductor is the typical approach to compensate for VD. The converse, lowering the ocpd rating effectively does the same. Either method limits the amount of current passing through a certain size (area) and length of conductor - preventing operation at a significantly reduced voltage.

 

[klassenl]

Under the Canadian code voltage drop has been in the text for 20 years.

 

[wyliesdiesels]

Under the Canadian code voltage drop has been in the text for 20 years.

Sure but is it enforceable?

Its in the NEC but not in a enforceable section.

 

[alfredeneuman]

The code doesn't enforce voltage drop but only provides "Informational Notes" on the subject so you won't find it. The allowable ampacities listed in 310.15B are subject to correction factors. VD hasn't made it to the enforced list.

So then why did you say that it was limited to 90A?

 

[mm08822]

So then why did you say that it was limited to 90A?

For the reason that accompanied that statement...."Permitted ampacity is reduced to limit voltage drop to approx 3%. The run is 250' long."

If you want to pretend vd doesn't matter that is your choice - use 100a cb. Would you use a 100a cb on the same size feeder if it were 500' long?

You can design/build better than code minimums. Page 1 of NEC - 90.1B.